Beags - The F-35C's OEW is a piffling 5500 pounds more than that of the F-35A, which has a performance impact, and the giant wing is not going to do wonders for your transonic acceleration.
If someone forced me at gunpoint to buy an F-35 (which is pretty much the US marketing strategy anyway) I would ask for an A+ with probe-and-drogue and no internal gun. It would have nearly as much internal fuel as the C and weigh 6000+ pounds less.
And srsly, folks, if you get in a guns fight in a JSF you (a) have already
ed up and (b) deserve what is about to happen to you. And strafing in a single-engine, densely-packed jet, in an era of mini guided weapons?
!
Funny thing is that they switched to the Gatling from the 27 mm Rheinmetall in 2003 because they thought that they had a big weight margin to play with.